Delta Tau GEO BRICK LV User Manual

setting of I3.  For these commands, the command acknowledgement character – <LF> or <ACK> – is sent 
after the data response, serving as an end-of-transmission character.  For computer parsing of the 
response, it is nice to have the <ACK> serve as a unique EOT character. 

Variable I4 determines some of the data integrity checks Turbo PMAC performs on the communications, 
the most important of which is a line-by-line checksum.  The Writing a Host Communications Program 
section covers this feature in detail. 

Variable I9 controls some aspects of how Turbo PMAC sends data to the host.  Its setting determines 
whether Turbo PMAC lists program lines back to the host in long or short form, whether it reports I-
variable values and M-variable definitions as full command statements or not, and whether address I-
variable values are reported in decimal or hexadecimal form. 

Many of the commands given to Turbo PMAC are on-line commands; that is, they are executed 
immediately by Turbo PMAC, to cause some action, change some variable, or report some information 
back to the host.  The command itself is thrown away after executing (so cannot be listed back), although 
its effects may stay in Turbo PMAC. 

Some commands, such as P1=1, are executed immediately if there is no open program buffer, but are 
stored in the buffer if one is open.  Other commands, such as X1000 Y1000, cannot be on-line 
commands; there must be an open buffer – even if it is a special buffer for immediate execution.  These 
commands will be rejected by Turbo PMAC (reporting an ERR005 if I6 is set to 1 or 3) if there is no 
buffer open.  Still other commands, such as J+, are on-line commands only, and cannot be entered into a 
program buffer (unless in the form of CMD"J+", for instance). 

There are four basic classes of on-line commands:  

• 

Port-specific commands, which only affect the action of subsequent commands on the same port;  

• 

Motor-specific commands, which affect only the motor that is currently addressed by the host;  

• 

Coordinate-system-specific commands, which affect only the coordinate system that is currently 
addressed by the host;  

• 

Global commands, which affect the card regardless of any addressing modes.  In the reference section 
of the manual, each command is classified into one of these types under the Scope descriptor. 

Each program that can use the COMMAND statement to issue on-line commands 
from within the card has its own motor and coordinate system addressing, 
independent of which motor and coordinate system the host is addressing.  
Changing a port’s addressing modes does not affect the program’s mode, or vice 
versa.